I can't get mp4 with 264 video to play no matter which decoder I choose. I get audio just no video. The files playback fine with either windows media player or videolan.
The decoder settings in the config app are only used when you play file types that GB-PVR recordings, ie .mpg, .ts, .dvr-ms. For other types of file (avi/mp4/mkv/etc), windows chooses what decoders use.
You can see what decoders its choosing by downloading GraphEdit, running it and selecting 'render media file' from the menu, then selecting your file.
I used graphedit and it shows I'm ussing ffdshow which is what I have selected in in config of GBPVR. The files play fine with windows media player and VLC but I'd like to use GBPVR to watch them like I do with all my other videos.
For this type of file it wont matter what you have selected in GB-PVR.
On thing that can happen if you're using ffdshow, is that it has a list of applications it'll be used by, and WMP and GraphEdit are on that list by default, and PVRX2.exe is not. This means these decoders wont be automatically selected by Directshow when you attempt to play this file type in GB-PVR. If you go into the ffdshow settings, you can add PVRX2.exe to the list of applications.